Beast Boy's History
As a child, Garfield Logan contracted with a rare illness called Sakutia and was cured by a serum from a green monkey. This serum had the unintended effect of turning his skin and hair green and gave him the ability to change into any form.
Doom Patrol and Teen Titans
Originally and currently known as Beast Boy, he was adopted by Elasti-Girl and Mento, members of the Doom Patrol. He later joined the West Coast team of the Teen Titans (known as Titans West), and was part of the New Teen Titans assembled by Raven. It was at this time that he took the name Changeling. He remained with various incarnations of the team, forming a close friendship with Cyborg.
He later began using the name Beast Boy again. Following a failed attempt to recreate "Titans West" as "Titans L.A.," he rejoined the main team.
He has also worked as an actor, playing the role of an alien in the TV series Space Trek 2020.
Death in the Family
Whatever team he is part of, he likes to joke around with people and make jokes of the situations the team get themselves into. However, this is only a facade. In reality, Beast Boy is a boy who has suffered many hardships in his life (both his real parents have passed away, and then his foster mother, whom Garfield became very close to, died in battle along with virtually all of the other Doom Patrol members. He was also part of the team. Also, his foster father was driven mad by a helmet he used to fight enemies). He also has lost many teammates and fell in love with Terra (a member of the Teen Titans) and was heartbroken to discover that she was a traitor working for Deathstroke and hated the Teen Titans with a passion. Even after her death, he refused to believe for a long time that she was a traitor and blamed Deathstroke for corrupting her and using her. As a result of all of this, he uses his jokes to cover the fact that he is scared of losing anyone else he is close to. Despite all of his hardships though, Garfield is friendly and upbeat.
His best friend is Cyborg (also a member of the Teen Titans). He is also close with Bette "Flamebird" Kane, a former Titan who helped save his life on an adventure in Los Angeles.
In the "Titans of Tomorrow" adventure, wherein the Titans glimpsed a grim, possible future, Beast Boy had changed his name to Animal Man (II) and fought alongside his fellow, fascist Titans to make the United States a police state. This future Beast Boy is shown as feral shaggy, and more bestial in appearance. He is also characterized as still bearing a grudge against a possibly-resurrected Terra, who, in this future, is a member of the more benign rival group Titans East.
He has recently become romantically attached to Raven. Raven had been developing feelings for him since her recent rebirth.
One Year Later
Due to the events of "One Year Later", they have apparently separated. After trying to hold together a ragtag band of Titans, once Robin returned Beast Boy left the team to rejoin the Doom Patrol and aid his adoptive parents. Following attacks on various former Titans, it was determined that the sons of Trigon were trying to destroy the group to establish a name for themselves. The Titans decided to reform to combat the threat. At the same time, Beast Boy tried to reconcile with Raven.
Following the Final Crisis, the newly formed Titans slowly broke apart, with Garfield rejoining the Teen Titans in order to polish them up after seeing their performance under the leadership of Wonder Girl. Raven followed soon after.